Apparatus for preventing curl of envelope flaps



Jan. 6, 1942. i o MlLLER I 2,268,610

APPARATUS FORPREVENTING CURL OF ENVELOPE FLAPS Filed Nov. 28, 1958 3 sheets-sheet 1 INVENTOR ATTORNIEY Jan. 6, 1942. v I o. E. MILLER 2,268,610

APPARATUS FOR-PREVENTING C L OE ENVELOPE FLAPS I Filed Nov. 2a, 1938 s Sheets-Shem 2 IELEM!!! ii INVENTOR' I 07% E. M/7 r:

I ATTORNEY o. E. MILLER ,610

APPARATUS EQR PREVENTING CURL OF ENVELOPE FLAPS Jan. 6, 1942.

Filed Nov. 28,1938 5 Sheets-Sheet 3 I, I I I Y Y INVENTOR Offo E. MIY/e/Y BY in o'R N EY I I I I I I I Q N v Q g Q .0 a. k 2 x U 2 65 i atented' Earn. 6, 1942 APPARATUS FOR PREVENTING CURL OF ENVELOPE FLAPS Otto E. Miller, Turner, Kans., assignor to Baltimore Paper Company, Kansas City, Mo., a cornotation of Missouri Application November 28, 1938, Serial No. 242,699

Claims.

This invention relates to envelope making machines and particularly to an apparatus for counteracting curl in the sealing flaps of envelopes incidental to drying the gum applied thereon.

It is well known that when gum is applied to sealing flaps, the surface tension of the liquid gum, and shrinkage thereof during drying, causes the corresponding areas of the flaps to cup in the direction of the gum, with the result that the flaps curl and cause warpage of the envelopes. When thus distorted the envelopes are unsightly and'appear to be improperly formed. The envelopes also do not stack readily or lie smoothly within the cartons in which they are packed. Another disadvantage is that it is diiiicult to feed distorted envelopes into printing machines when w it is desired to print them after formation.

It is, therefore, the principal object of the present invention to provide an apparatus for preventing and removing curl in the sealing flaps of envelopes so that the flaps \will lie flatly against the bodies of the envelopes and without causing distortion thereof.

In accomplishing this and other objects of the invention, as hereinafter pointedout, I have provided improved details of structure, the preferred forms of which are illustrated in the accompanying drawings, wherein:

Fig. l is a fragmentary perspective view, partly in section, of an envelope machine equipped with the present invention, and illustrating the method of treating the sealing flap of an envelope so that it will lie flatlyagainst the body thereof when the flap is subsequently folded.

Fig. 2 is a plan view of the mechanism shown in Fig. 1.

Fig. 3 is an enlarged vertical section on the line 33 of Fig. 2.

Fig. 4 is an enlarged detail sectional view showing the presser blade cooperating with the groove in the platen to effect bending of the sealing flap so as'to counteract curling tendency thereof inoidental to the sealing gum applied thereon.

Fig. 5 is a perspective view of an envelope blank partly folded and showing the sealing flap immediately after it has passed under the presser blade, and particularly illustrating the reverse curvature that has been imparted therein.

livered through the flap treating mechanism .1, as.

Fig. 6 is a diagrammatic perspective view' of the different operations performed on an envelope blank in an envelope machine, wherein the sealing gum is applied, dried, and treated in accordance with the present invention. I

Fig. 7 is a sectional view similar to Fig. 4, but showing a modified form of presser blade.

Referring more in detail to the drawings:

I designates a portion of an envelope making machine of standard type, and which includes side frames 2 and 3 carrying the various operating mechanisms required in the formation of envelopes from blanks, including the blank advancing mechanisms. For example, envelope blanks a are removed singly from a stack 11 and advanced by a suitable conveyor means to a point c where the blanks are moved in fanned out, superimposed relation, as at d, so that only the portion of the sealing flaps e thereof are exposed for application of the gum by the adhesive applicator A. The blanks are again separated, as at I, and conveyed through a drying zone 5, between belts 6, so that the gum 9 that has been applied thereon is dried suiiiciently to prevent smearing and sticking thereof when the blanks begin their travel through the flap folding sections of the machine. When the blanks are delivered from the drying section they pass through the side flap folding mechanism (not shown), wherein the side flaps h are folded over the front portion i of the blanks. The blanks are then successively delater described. The blanks then continue their travel through the machine under gumming apparatus 8, which applies gum to the bottom sealing flaps a, and through bottom and sealing flap folding mechanisms where the respective flaps e and 7' are folded over the side flaps h, and the folded envelopes are then stacked on edge, as at k. The envelopes collecting in the stack are then removed and deposited in cartons for shipment.

When the gum is applied to the sealing flaps the surface tension of the'liquid gum causes the corresponding areas of the sealing flaps to cup in the direction of the gum, and the drying thereof in the drying zone further aggravates the cupping tendency incidental to shrinkage of the gum, with the result that the flaps are distorted and tend to curl upwardly by the time they reach the side flap folding mechanism. I therefore provide a mechanism 1 wherein the sealing flaps are caused to curve in the opposite direction, thereby counteracting the normal curling tendency so that when the flaps are folded over the body of the envelopes, they will lie flatly thereagainst when the envelopes thus treated stack smoothly and are readily applied in the cartons.

The'mechanism 1 consists of a platen-like plate w 8' over which the partly folded blanks are 0on veyed, and which has agroove 9 extending trans- I tact with the sealing flaps, at the time they are moving over the groove 9.

The presser bar 13 consists of a fiat blade of .sufllcient length that it projects beyond the ends of the sealing flap of the envelopes, as shown in Fig. 1. The pressen bar is of relatively narrow width and has a rounded edge H to contact the flaps. The bar is supported on edge by stems l and I5, slidably mounted within ears I! and I8 carried on a cross bar IS. The lower ends of the stems are slotted, as at 20, to snugly receive the upper edge of the presser bar, as shown in Fig. l. The presser bar is preferably anchored in the slots of the stems by pins 2| so that the bars may be used having lengths corresponding to the width of the envelopes being formed. The stems are interconnected byan intermediate cross bar 23 having its ends secured to the: stems by fastening devices 24. The stems are connected at their upper ends by a cross head 26, the ends of the stems being provided with reduced threaded extensions 21 and 28 that extend through openings in the ends of the cross head. The cross head is drawn, by nuts 29 and 30, into contact with the shoulders formed about the base of the extensions, as shown in Fig. 1.

The supporting cross bar 19 extends transversely of the machine in upper spaced relation with the blanks and has its ends secured to lugs 3| and 32 fastened to the side frames, as shown in Fig. 2. The presser bar is normally retained from contact with the bottom flaps and body portions of the blanks passing thereunder by a spring 33 having one end attached to a pin 34 carried by the cross bar 23 and its other end connected with a pin 35 projecting laterally from the bar l9, as shown in Fig.1.

In order to move the presser bar into contact with the sealing flaps, in timed relation with travel of the blanks, I provide a cam mechanism generally designated 36, which is operated from one of the forwarding rolls 31 of the envelope machine. The cam mechanism includes a rocker arm 38 that is pivotally supported on a pin 39, carried by a cross bar 40 extending parallel with the bar l9, and which has its ends supported on lugs 4l42 at the ends of the bar 19 and on an intermediate lug 43 also carried by the bar I9. The rocker arm has one end 44 projecting over the center of the cross head and carries a roller 45 that is rotatably mounted on a supporting pin 45 fixed to the arm, so that the periphery of the roller contacts with a wear plate 41 on the cross arm, as shown in Fig. l. The opposite end of the rocker arm is pivotally connected by a pivot pin 49 with the upper end of a push rod 50. The push rod 50 is slidably mounted in a suitable also retains the cam roller in engagement with the cam so as to eliminate the necessity of additional springs or the like. The presser bar is offset from the side In of the groove 3 so that the flap will pass freely therebetwe en but will be held to the edge I2. i

In operation the presser bar descends in close relation with the side edge H) of the groove 3 so that the flap is deflected into the groove and bent over the edge I2 without tearing or creasing thereof as the flap is being drawn under the bar incidental to advancement of the blank by the forwardin rollers. As the gum portion of the blank passes over the edge II, the tension and rigidity of the gum, including the fibres of the paper, are sufficiently broken to destroy curling, tendency of the flap in the direction of the gum, and to impart a reverse curl thereto so that if there is any returning tendency for the flap to curl in an upward direction, this tendency is counteracted by the reverse curl shown in Fig. 5. Therefore when the sealing flaps are folded over the body portion of the envelope, and the envelopes delivered in stacking relation, the sealing flaps will lie flatly thereagainst and no distortion will occur in the body of the envelope.

Fig. 7 shows a slightly modified form of presser bar in that it is provided with a.roller 55 extending along its lower edge to contact the sealing flap.

What I claim and desire to secure by Letters Patent is:

1. In an apparatus of the character described, a platen plate having a transverse groov forming a breaking edge, a pressing bar, spaced stems carrying said bar, means reciprocably mounting guide 5! on the side frame; I, and carries a cam the stems, a cross head connecting the stems, a spring connected with the cross head for supporting the bar in one position, a roller engaging the cross head, a rocker armsupporting the roller, cam means for actuating the rocker arm to effect movement of said pressing bar in opposition to said spring, and means for advancing envelope blanks across the platen plate while they are engaged by the pressing bar.

2. In an envelope making machine, means for advancing partially formed envelopes with the gummed sealing flaps thereof in trailing position, a supporting member having a flap supporting surface intercepted by a vertical surface on the advance side thereof with respect to the direction of travel of the envelopes to-form a breaking edge? a blade-like member substantially coextensive with the breaking edge, a yoke-like frame carrying the blade-like'member, means supporting said yoke-like frame for reciprocation of the blade-like member in a plane parallel with said vertical surface and offset therefrom a distance substantially the thickness of the flaps, and means for reciprocating the yoke-like member on said supporting means to effect bending of said sealing flaps over said breaking edge by said blade-like member while they are being advanced by said advancing means.

3. In an envelope making machine, means for advancing partially formed envelopes with the gummed sealing flaps thereof in trailing position, a supporting member having a flap supporting surface intercepted by avertical surface on the advance side thereof with respect to the direction of travel of the envelopes to form a breaking edge, a blade-like member substantially coextensive with the breaking edge, a yoke-like frame carrying the blade-like member, means supporting said yoke-like frame for reciprocation of the blade-like member above said supporting surface in a. plane parallel with said'vertical surface and offset therefrom substantially the thickness of the flaps to bend said sealing flaps over said breaking edge by said blade-like member while they are being advanced by said advancing means, a spring for retaining the frame in retracted position with the blade-like member spaced above the breaking edge to pass said envelopes, and timing meaw operating in synchronism with the advancing means for moving the yoke-like frame against action of the spring to carry said blade-like member in bending contact with the breaking edge while the entire gum portion of the sealing flap is being moved thereacross.

4. In an envelope making machine, a member having a flap supporting surface intercepted by a substantially'vertical surface to form a substantiallyright angular breaking edge, means for advancing partially formed envelopes over said breaking edge with their sealing flaps in trailing position and with the gum side uppermost, a

with said intercepting vertical surface, and

means for reciprocating said blade-like member to bring the breaking edge thereon into contact with the sealing flaps and to bend the sealing flaps over said breaking edge of the flap supporting surface while the envelopes are being advanced thereover.

5. In an envelope making machine, means for advancing partially formed envelopes with the side flaps folded over the body portions thereof and with the sealing flaps in trailing position, a. supporting member in the path of said partially formed envelopes and having a substantially fiat supporting surface intercepted by a vertical surface to form 'a substantially right angular breaking edge, a blade-like member substantially coextensive with the breaking edge and having a similar reversely arranged breaking edge, means supporting said blade-like member for reciprocation in a plane substantially parallel with said intercepting vertical surface and offset therefrom a distance substantially the thickness of said flaps, means for reciprocating said bladelike member to bend the sealing flaps over said breaking edge, and gripping rollers engaging the partially formed envelopes adjacent the folds of the side flaps to draw the sealing flaps between said breaking edges while the sealing flaw are retained in bent position.

OTTO E. MILLER, 

